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Grow It 3-5 / Week 07 / Thursday
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Week 07 · Seeds on the Move

Thursday

Floaters, poppers and droppers
// How seeds travel to new places
⏱ about 15 min

Thursday: Floaters, Poppers and Droppers

Rocket fills a bowl with water. "I bet every seed sinks," he says. He drops in a bean. Plop!

Then he stops. "Wait. I should test more than one seed."

Raven nods. "What do you notice about each one in the water?"

Nova blinks softly. "Predict first," she says. "Then let the seeds show you."

Seeds that float

Many plants that grow near water have seeds that float.

Plants along streams and rivers can send floating seeds downstream.

The seeds wash up and grow in new spots.

Size does not decide if a seed floats. Some big seeds float, and some tiny ones do too.

Seeds that pop

Some plants have seed pods that dry out in the sun.

When the dry pod bursts open, it flings its seeds out.

Forest scientists studied one weed that throws its seeds up to 15 feet!

That is a big jump for a little seed!

Seeds that drop

Some heavy seeds just fall. Gravity pulls them down.

Big acorns often land near the oak tree, then roll or get carried.

Gravity is the simplest seed ride of all.

FLOATER, POPPER OR DROPPER?
  • Read the question.
  • Tap your answer.
A seed lands in a stream and drifts away. What kind of ride is that?
A dry pod bursts and seeds fly out. What kind of ride is that?
A heavy acorn falls straight down to the ground. What kind of ride is that?

Float or sink test

  • A bowl of water
  • Two dry beans, two dry peas and a few grains of rice
  • A spoon
  • A paper towel
Safety first
Seeds are for testing, not eating. Nothing goes in your mouth.
Wipe up spills so nobody slips.
Wash your hands when you finish.
  1. Copy the table below on paper.
  2. Write your prediction for each seed: float or sink.
  3. Gently drop in one kind of seed.
  4. Wait and count to 30. Write what happened.
  5. Scoop the seeds out with the spoon and test the next kind.
SeedMy predictionWhat happened
bean
pea
rice
Did your prediction match for every seed? Type yes or no.
WHY THIS EXERCISEScientists check predictions against results. A miss teaches us something new!
StatementTrue or false?
Some seeds float down rivers to new places.?
Only big seeds can float.?
Some dry pods burst and fling seeds.?
Gravity pulls heavy seeds down.?
WHY THIS EXERCISEWater, bursting pods and gravity all move seeds.
A POPPER SEED'S TRIP
  • ?The pod dries out in the sun.
  • ?The dry pod bursts open.
  • ?A seed sprouts in its new spot.
  • ?The plant grows a seed pod.
  • ?Seeds fly out and land on the ground.
WHY THIS EXERCISEA drying pod bursts and flings seeds away from the parent.
Try it
Check your bean plant and water it if the soil feels dry.
Add one line to your plant log.

Brilliant testing, even when predictions missed! Tomorrow we think like engineers and plan a seed design.

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